The invention is in the field of universal joints as applied to hand tools and also hand tool drive mechanisms.
Probably one of the most difficult and frustrating tasks of a mechanic, especially an automobile or vehicle mechanic, arises in trying to gain access for mounting or removal of bolts, screws, and the like, which require rotation, from a motor or other piece of machinery whose design criteria may have included adaptability to swift assembly on the assembly line, and perhaps compactness and the ability to interfit with other closely spaced equipment and installation, but there having been given little or no thought by the designing engineers to accessibility of parts and bolts for removal and repair during the routine maintenance which is bound to come up over the life of the machine.
Access and removal of a bolt, for example, can sometimes be attempted from a direction perpendicular to the bolt shaft with an open end wrench. Not infrequently the wrench head can be inserted from this direction to grip the bolt, but inadequate back and forth space exists to manipulate the wrench and remove the bolt.
Another typical variation of the above-mentioned dilemma arises when the bolt must be accessed from an angle slightly to the head side of perpendicular to the bolt length so that an open end wrench will continually slip off the bolt head but the angle is too steep for proper removal with a socket wrench, even one having a universal joint head, as these are typically impractical at angles of greater than about 60.degree..
There is a need for a wrench having a jointed head which will fit snugly and orthogonally over any accessible bolt head and which can be moved either linearly or rotationally in any direction at all in the machinery in which there is freedom to move and still cause the bolt in question to be removed or installed as the situation requires.